Automatic potential-regulator.



No. 726,234. v PATBN'I'ED APR. 21, 1903. I A. TIRRILL. AUTOMATIC POTENTIAL REGULATOR.

APPLIOATION FILED SEPT. 25, 1902.

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b MD Np. 726,234. PATENTED APR. 21,1903

A. A. TIRRILL.

AUTOMATIC POTENTIAL REGULATOR.

APIPLIOATION FILED SEPT. 25. 1902.

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% W -flllen fLTirrilL %W WW 04w} No. 726,234. PATENTED APR. 21, 1903.

A. ALTIRRILL. I

AUTOMATIC POTENTIAL REGULATOR.

APPLIOATION FILED SEPT. 25. 1902.

N0 MODEL. 10-SHEETSBHEET IIIIIIIIH INJENTO JQHQIJQTIITHI.

Y b Y W w No. 726,234: PATENTED APR. '21, 1903.

A. A. TIRRILL. AUTOMATIC POTENTIAL REGULATOR.

APPLICATION FILED SEPT. 25, 1902. N0 MODEL.

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'No. 726,234. PATENT ED APR. 21, 1903.

A. A. TIRRILL.

AUTOMATIC POTENTIAL REGULA'HJR,

APPLICATION FILED SEPT. 25, 1002.

' no MODEL. 10 SHEETS-SHEET a.

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PATENTED APR. 21,1Q02,

A. A. TIRRILL, AUTOMATIC POTENTIAL REGULATOR.

APPLIOATION'IILEDSEPT. 25, 1902.

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No, 726,234. PATENTED APR.21,1903L A. A. TIRRILL'. y AUTOMATIC POTENTIAL REGULATOR.

APPLIOATION FILED SEPT. 25,-1902. H0 MODEL. 10 SHEETS-SHEET 8.

Witnesses. Inventon M 1224 flllenfl Tirrill,

No. 726,234. PATENTED APR. 21-, 1903. A. A. TIRRILL.

AUTOMATIC POTENTIAL REGULATOR.

APPLIUATION FILED SEPT. 25. 1902.

N0 MODEL. 10 SHEETS-SHEET 9.

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5; (\1 m (L J WITNESSES 1 INVENH QRI JdnemqTim-m; W by No. 726,234. PATENTED APR. 21, 1903.

A. A. TIRRILL.

AUTOMATIC POTENTIAL REGULATOR.

APPLICATION FILLED SEPT. 25. 1902.-

IN) MODEL. 10 SHEETSSHBET 10.

relay-contacts.

Original application filed December 16, 1 901. Sari To all whom it may concern:

Be it known that LALLEN A.'11Rnim.,a citi- -zen of the United States, residing at Schenectady, county of Schenectady, State of v New 5 Yorlr,haveinvented certain new'and useful Improvements in Automatic PoientiaLRegtr lators', (division of my application Serial No. 86,116, filed December 16, 1901,) of which the following is a specification.

The present invention consists in improvements upon the invention describedin United States Letters Patent No. 620,514., dated February 28, 1899, and in application for United. States Letters Patent, Serial No.12,721, filed April 13, 1900. The subject-matter of said patent and application is especially.-applicable to the regulation of directcurrent dyna- A primary object of the presentinvention is to automatically regulate the potential of alternating-current dynamos, and in achieving this object many of the features of the said patent and application are utilized. While the regulation of alternating-current dynamos is the prime purpose of the present invention, it is applicable to the regulation of direct-current dynamos, as will be heroin-. after pointed out.

The diagram, Figures 1 and 2, shows the electricalcircuits and the variousinstru ments diagrammatically. Fig. 3 shows a front view of the principal instruments which in practice are grouped on a single slab. Fig. is a side view, 'partly in section, of the alt-cr nato'r controlling-magnet AC. Fig. 5isa detail of the hand-rod for 'movin g the core ofsaid magnet A-G. Fig. 6 is a cross-section-of said core. Figs. 7 and 8 are detail views of'the Fig. 9is a front view of the core of the alternator controlling-magnet and of its lever, showing the dash-potin longitu- Fig. 10 is a front view of one end of the lever carrying the contact which is controlled by the direct controlling-magnet,

Figs. 9 and 10 being shown in thepsame relative position that the parts illustrated thereby Fig. 1.1 is a ve iical longitudinal sectionlthrough thelever of the alternator controlling magnet. Figs. '12 and l3 are dedinal section.

UNI ED STATES PATENT OFFICE.

ALLEN A. TIRRILL, OF SOHENEC'FADY, NEYV YORI pASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

AUTOMATIC POTENTlAL-R'EGU LAT srnclrrcamzon forming part of Letters Patent No. 726,234, dated 'A n'l 21, 1903.

al No. 86,116. Divided and this application filed September 25, 1992. Serial No. 124,838. (No model.)

tails of the starting'switch mechanism. Fig. 5c 14 is a cross-section in the plane indicated by the line 14 14. in Figs. 4 and 9. Fig. 15 is a plan view of the series transformer which is used to compensate for loss of potential in the working line.. Figs. 16 and 17 are vertical. sections (in planes at right angles to each other) of said transformer. Fig. 18 is a plan view of one of the coils of the transformer with the upper core removed. Fig. 19 is a side view of the levers at and all of the magnets AC and DC, respectively. In' this instance the relative position of the levers is the reverse ofwhat is shown in Fig. 3. Fig.

20 isa plan view of said levers. Fig. 21 is an end view of the lever dl, looking at itin the direction of the arrow 21 in: Fig. 19,.and

it isa verticalsection of the lever al in the plane indicated by the line 21 21 in Fig. 19. Fig. 21 is on a larger scale than Figs. 19 and 20. Fig. 22 is aside view, partly in section, of the relay-magnet. Fig. 23 is a plan view, and Fig. '24 an end-view, of the contact end of the armature and of the corresponding end of the post which carries the other relay-contact. Fig. 25 is a simplified diagram, similar to Fig. 1,showing the difierences involved by this preferred arrangement. Figs. 26 and 27 show the invention applied to the regulation of direct current generators. Fig. 28 represents its use in connection with a plurality of alternating-current generators having a common exciter.

I The present invention comprises many inrproved structural features and also different applications of its fundamental idea and amplifications which render its operation: more perfect. "In orderthat allot these matters may be clearly understood, it seems expedient at the outset to first describe the foundation idea of' the invention-reduced to a simple form and stripped of nnmerolis additions and details, many ofwhich, as will hereinafter appear, are of great importance.

To this end referencewill first be made to the diagram-Fig. l of the drawings, which 5 illustrates the baldoutlines of the invention in an extreme] elementary way','only a single refinement eingillnstrated. In-thisdiaeach pivoted at 1'). .is balanced against the pull of the solenoid gram A is an alternating-current dynamo, A A the supply-mains fed thereby, and E is the exciter. As illustrated, the fieldaof the alternator is in the mains E E of the exciter. A hand-adjusted resistance 1) is in the excitermains, and there is a regulating resistanceB in the exciter-shunt. This regulating resistance may also be hand-adjusted; but when once thus adjusted it is adapted to be automatically cut in and out to effect the automatic regulation, its action in this respect being similar to that of the regulating resistance of the said application Serial Nix-12,721.

There are two controlling regulating-magnets AG and D0, which, as shown, are solenoids, with their respective cores so located that increase in potential lifts one solenoidcore and depresses the other. The solenoid DC is in a shunt E E from the exciter-mains, and the solenoid A0 is in a shunt A A from the alternator-mains, and hence these solenoids may be appropriately termed the direct controlling-magnet and the alternating controlling-magnet, respectively. The cores of these two solenoids are hung, respectively, frotnthe outer ends of levers (U and al, The direct-magnet ,core

by spring 6, while the other core may be balanced by gravity only. The said two levers are pivoted one above the other, and one carries a contact 0 and the other a contact 0, these constituting apair of coiiperating contacts capableof approach and separation as their carrying-levers oscillate under the varying excitations of the two solenoid-cores. The core of the alternating controlling-magnet AC is connected with a suitable retarder, such as a dash-pot P. These two contacts 0 c constitute the terminals of an electric circuit, which preferably includes a regulating relay magnet D. This relay may receive electric current from any source of genera-- tion and conveniently from the exciter, but is shown in a circuit D D supplied. from an ihdependent source RG. v

The relay-armatu re controls a pair of regulating-contacts d d, one movable with the armature and the other being carried by any suitable support. These contacts d (1' constitute the terminals of an electric circuit B B which is a shunt around the regulating resistance B in the exciter-field circuit.

In the arrangement shown in the diagram, Fig. 1,when the solenoid-contacts cc are open the relay-circuit D D is broken, and hence the relay-armat ore is moved up by the spring f, and hence the contacts d-d come in con-' tact, thus closing the regulating-circuit B B and thereby shunting the entire regulating resistance. When, however, the solenoidcontacts 0 0' come together,the relay-oi rcuit D" D is closed, the regulating-circuit B B is opened, and hence'the regulating resistance B is thrown into circuit.

When the regulating resistance is shunted,

the potential of the exciter rises, and thus 7 these circumstances the tnain contact-l the potential of the alternator and on the supply-mains is increased, and hence in turn the ance into action and. decrease in potential -.pnts it out;of action. The same effects, generally speaking, are produced from any change in potential on the feed-mains due to changes in the load produced by the bringing into and'out of action any of the current users fed by the alternator'or from any other cause. It ishence evident that by properly proportioning the regulating resistance the potential can be maintained substantially constant, as explained in full in the aforesaid application Serial No. 12,721;

The reasonfor the employment of the two solenoids will be understood from the following discussion: At the outset it will be assumed that the regulator is in operation and that the alternator voltage is steady. linder oints c and c are successively'opening and closing at a rate necessary to maintain such voltage, and the two levers al and (Z1 are moving slightly, aZ being practically stationary, as it is retarded by the dash-pot P, while lever (ll is supplying most of the motion necessary to open and close the relay-circuit. This successive opening and closing of the main contact-points is caused by the slight successive rise and fall of the exciter voltage, due to cutting out and in the regulating resistance 13 by the opening and closing of the relay-circuit throughthe main contact-points. This slight rise and fall in esciter voltage'theoretically, and probably actually to a siightdegree, simultaneously affects the alternator voltage, so that both main contact-pointsare actuated by the change in voltage of the currents in their respective magnets AG and DC, and both contribute to, the result of holding the voltage steady. The lever dl is held in position by the pellet the direct controlling-magnet DC on its core against its spring 6', which may be adjusted as hereinafter described. As the voltage of the exciter-currentincreases or decreases the pull against said spring of said magnet DO increases .or decreases, hence tilting lever all one way or the other until the force of said spring (which is increased or di' minished as said lever moves) becomes equalized. It will be seen then that the end of lever dZ upon which contact 0 is carried will assumea position nearer to or farther from its normal position according as the exciter vol- I oo magnet and (acting the main contact-point controlled thereby,

tage is higher or lower and as the pull of magnet DC is correspondingly increasedor diminished. Now let it be assumed that the voltage in the alternating mains is increased. This increases the pull of alternating controlling-magnet AC, causingits core to travel up into said magnet, thereby pushing up on lever a! and causing contact 0 to remain for a longer period in touch with contact 0. This tendency of the contact-points to remain together, acting through the relay, causes the rheostat or regulating resistance to remain cut in longer than would otherwise be the case, thereby lowering the voltagein the exciter and its magnet DC. This permits spring e to pull down the lever all as the voltagein the exciter is lowered until the exciter voltage reaches the stage necessary to reduce the alternating voltage to the desired normal point. It will be remembered that as the exciter voltage falls the alternator voltage falls, reducing the pull'of alternating controllingmagnet AG, and consequentlythe tendency of contact-point c to remain longer in touch with contact 0. As soon as the cxciter voltage reaches the necessary point and the alternating voltage its normal point, the movement of lever dl away from its normal position of contact-point c ceases, the lever being tilted in a position determined by the voltage of theexciter workingthrough the exciter-' magnet against spring e, and contact point 0, carried on lever aZ, loses at the same instant its tendency toremain longer in' touch with contact-point c, the lever cl being then tilted sufiiciently to keep point 0 near enough to point e to continue its functions; The

voltage in the alternatormains'being restored and the voltage of the exciter being reduced to counteract the-disturbing factor, the two contact-points continue to operate in their new position, tending to remain enough longer in touch to keep the eXciter-rheostator regulating resistance out in for a sufiicient preponderance of time to keep the exciter-current at its new voltage. Any tendency in the exciter voltage to rise is checked, because such tendency, however slight, will cause a like teudency in the altern ato r voltage, increasing the pull of the magnets AC and" DO and tending to'hold points 0 and 0 longer in contact, and thus t6 keep the voltage of the exciter down. Any decrease in voltage in the alternating mains will be corrected in an inverse'manner, the points 0 and o finally assuminga point determined-by the new exciter voltage, which will become established at exactly the point necessary to counteract the disturbing factor.

This change in the tilt of said levers and of the position of the contact-points may be summarized as follows: Any change in the alternator-mains will correspondingly afiect the strength of the alternating controllingthrough its lever upon which saidcontact-pointwill thereby have a tendency to remain for a longer period in lever and its contact-point, and by the joint contact with or separated from the other point) will cause a change in exciter voltage sufficient to restore the alternator voltage to the desired point. This change in exciter voltage will change the position of the contact-point controlled by the exciter or direct controlling-magnet and its connections until the force of the exciter or direct controllingmagnet equalizes with the force of its opposing spring. The alternating lever and its contact-point will assume a position corresponding to the new position of the exciteraction of the two contact-points actuated by the influence of the currents in their respective magnets the voltage of the exciter will be held steady at the point necessary to hold the alternating voltageat the desired point. The dash-pot connected with the core of the alternating magnet serves the double purpose of moderating the movement of the lever and contact-point connected therewith when a change in voltage occurs and of preventing excessive movement of its contactpoint while the regulator is holding the voltags steady when no external disturbing cause is. afiecting the alternating Voltage; while the exciter-lever and contact-point are left free to move as the proper operation of the regulator requires.

' It will be noted that the foregoingoperation involves a pair of contacts movable toward each other which control the action of the too regulating resistance and that one. of these contacts is. controlled in its movement by change of voltage in the exciter-mains and the other by change of voltage in the alternator-mains. are concerned the controlling electromagnetic devices for these contacts-may be of any suitable kind and their connection with the contacts can be eifected in any desired way which will produce the results,

- The contacts 0 0' might directly control the regulating resistance shunt; but practice/ shows that they would quickly be destroyed and rendered inoperative by sparking, and hence the relay D is used for the-reasons fully set forth in said Patent No. 620,514: and said application Serial No.- 12,721.

As abovesuggested, the relay may be actuated by any source of electricity, and in many instances-as, for example, where the change in load is excessive-it is desirable to actuate it by an independent source, so that the action of the relay may not be affected by change in the exciter voltage. A small sepathat with the direct controlling-magnet omitted.(which,in effect,would representthe device setforthin said application, Serial No. 12,721,)

the ei gciter voltagewould not be established As far as the broad features ment when applied to the regulation of alternating machines is the combination of the exciter and alternator controlled cooperating contacts, which in turn control the action of thev regulating resistance. 4

In order that the various details of the present improvements may be unde'rstocd,

there will first be described one successful .practical embodiment thereof.

A In the description no reference to modifications or amplifications will be'made, such matters being reserved until after the single embodiment has been' fully described.

As shown in Fig. 3, the direct controllin magnet DC, the alternator controlling-magnet AG, and the relay-magnet ,D are all mounted on a common marble (or equivalent) slab 100. The construction of the direct controlling-magnet DC and of its lever dl and the means for adjusting its spring e are the same asinsaid application Serial No.12,721,"

and hence need not be here specifically described. The only difference is in the manner in which the contact 0 is connected to the lever dZ.- As best shown in .Fig. 10, the

contact 0 (of platinum or other'suitable material) is carried near the end of an elastic or spring arm 1, which is connected with a post 2, which is longitudinally adjustable in a slot 3 in the lever (ll, so that the position of the contact maybe adjusted at will, and the contact itself is a yielding one. An adjustable stop 9 limits the swing of lever dl.

- The coil of the alternator controlling-magnot AC, Figs. 2 and 4, has two sets of windings 4 and 5, the purpose of which will be hereinafter explained; but otherwise its coils are constructed like those of arr-ordinary solenoid. The core or armature 6 is composed of a bundle oflongitudinally-extending laminated wires-or small rods of soft iron, as best shown in Fig. 6, suitably held together by bands f of vulcanized fiber or other material and connected with a central longitudinal supporting-rod 7,which is pivotally suspended at 8 to the outer end of the lever al, as best shown in Fig. 9. Said lever al is composed of two sections 9 and 10, (see Fig. 11,) which are adj ustably connected by screws 11- and slots 12,'so that the position of the contact 0,

carried by the section 10, can be adjustable, in order that it may properly register with the other contaot, c. The contact 0 is in the form of a screw tapping through the section 10 for adjustment and held in place by the set-screw.

13. The other lever-section, 9, is pivoted by arbor 14 (see Fig. 4) in a suitable fixed bracket 15. On the arbori is an adjustable collar 16, held place by set-screw 17, to which collar is attached one end of a spring 6, the other end of said spring being adjustably attached to a fixed post 18, (see Fig. 3,) said spring, if employed, aiding gravity in moving the core against the pull of the solenoid. Binding-screw 19 connects the conducting-wire D to the lever al. An adjust able stop 9 limits the swing of the lever al.

The lower end of the rod 7 of the core of the magnet AC enters the dash-pot Pand hasa piston 20 fitting the cylindrical interior of said dash-pot, as best shown in Fig. 9. The dash-pot cylinder communicates by ports 21 21 above and below the piston with a longitudinal passage 22, which is controlled by'a valve 23, which is vertically adjustable to and from its seat, so as to regulate the effective capacity of the passage 22, thereby enabling the sensitiveness of the dash-pot to be regulated. Light machine-oil is preferably used in the dash-pot, and its flow, as ihe'pisten moves up and down, is regulated by the adjustment'of the valve 23. When the regulater is not in use, the weight of the core 6 holds the lever al against stop g, as shown in Fig. 9, thus separating the contacts 0 0', since spring 6' at the same time also holds the lever dl against the stop g.

In starting the regulator in operation it is important to bring the contacts together, and

to enable this to be done means are employed for lifting the core 6. 1 These means include a startin -rod 24:, which slides vertically in fixed guides 25 25 (see Figs. 3, 4-, and 5) and which is held in place by adjustable collar 26. Said starting-rod'has adjustably secured to its upper end a fork 27, (see Fig. 14,) which straddles the stem or rod 7 beneath the core 6. (See Figs. 4 and 9.) \Vhen the startingrod is pushed up by the push-button on its lower ehd, the fork 27 encounters the lower end of the core 6, thereby raising said core, and hence bringing the contacts 0 together. When the contact has been made, the starting-rod is releasedand drops down out of the way by gravity.

elevates the core, and as the current decreases the core drops under its own weight. To aid in the regulation of the magnet AO,a counterpoise 28 is adjustable on the section 10 of lever al, as best shown in Fig. 9.

Non-inductive resistances are used, as in said application Serial No. 12,721, and for this purpose incandescent lamps may be used. The sockets for such lamps are illustrated in Fig. 3. As here shown, the sockets F and FF are in the circuit of the magnet DC, and the sockets G and GG are in. the circuit of the relay D, as in said application Serial No. 12,721. Two additional sockets 29 29 in the present case are shown, which are in circuit with the alternator-magnet AC, as indicated in the diagram Fig. 2.

The relay-magnet D is a diderential magnet in all respects like that of said application Seriai Nc.12,'721 with coils R and S, Fig; 2,

'armaturo,--(see Fig. 7,) and said post is held in place by set-screw 320. Thisienahles the 'contact d to be properly adjuste'drelatively to the spring-mounted contact at.

Reversing hand-switches H and I (see Fig. 3) are employed,'just as in said application Serial No. 12,721, to reverse, the flow of the current from time to.time through the contactsc c and d d, respectiyely, and the same 4 switch N is employed to render inoperative or 1-5 operativethe regulator at will.

I "As heretofore stated, the coil'of-the magnet AG has two windings 4 and 5, of which the winding 4- is in circuit'with the shunt A A from the alternator-mains. 'Preferably and as shown in Fig. 2 this winding 4: is not in a direct shunt, but is in circuit with the secondary of a parallel or multiple transformer "l, the primary of which is in the sh not A A.

By thus placing the iiiagriet AG in a transformed shunt the voltage is reduced 'to practical limits for use in tin regulator. The nonindnctive resistances 2h :29 are in this transformed shunt-circuit and have the same function as the resistances F in the circuit of the direct ontrolling-magulet DC. The other winding, 5, of the magnet AU is in circuit with the secondary coil of a special series transformer U forqpurposes which will he fully explained after describing the construction of the said transformer.

As shown in Figs. 15 to 17, the transformer U is mounted on a-slab 101, separate from the slab carrying the other instru-mentalities. The primary coil 32 of the transformer has a limited number of convolutions of heavy wire 33, through which may new the whole or a portion of the total current ofone of the mains, as A of the alternator, as "indicated in Fig. 2. former has a large number ofconvolutions of fine wire 35 in circuit with the 'wi-n'ding 5 of the magnet AC. The two coils 32 and fi-thavetwo horseshoe-cores 36 37com mon toboth coils.

Both cores are laminated, each comprising a plurality of thin horseshoe-shapedsoftfiron plates bolted together and secured to suit One leg of each core.

able cap-plates 38-39. enters the primary coil and the otherleg enters the secondary coil. mains in its normal place; but the lower core is vertically adjustable by means of the adjusting-stem 40, post 41, and nuts 42 42, whereby the transformed current in the secondary can be regulated. Each leg of each core is substantiallyrectangular in cross-sec tion, as indicated in Fig-18. Thepurpose of this series transformer is to compensate for line losses in the working circuit of the alternator. It is well known in transmitting electrical energy that the line loss increases substantially proportionally to the current flowing. It is frequently the case that the The secondary coil'34 of this trans- The upper core regenerating plant is located at a considerable distance from the place where the energy is to' be used. Consequently it is necessary to raise the voltage at the generator as 'the working load increases in order to maintain constant voltage at the place of use. The series transformer U is to effect this purpose. This transformer is placed in series with one of the mains, so as to take adefinite proportion of the total current.

ary of this transformer and is so connected up that the current flows therein in pulsations opposite in ,direction to those in the other winding, 4, through which the current from the parallel transformer T liows. The ampere-turns in the main winding 4 aregreater than those in the auxiliary winding 5, and consequently the current in themain winding 4 is that which energizes the magnet AG, and the effect of current flowing through the auxiliary winding 5 is simply to diminish the effect of the current in the main winding 4. Let it be assumed that none of the consumers are using the current. Then practically no current will he flowing through the working mains, and-consequently no current will flow through the auxiliary winding 5, and hence the main winding 4 will have its maximum effect on the re ulator and, it may he assumed, will then maintain the transformed Voltage at 110, for example. If then the full working load is brought into action and its effect would be to cause the transformed voltage at the distant place of use to drop to 100, owing to line loss, it is evident that the voltage at the generator mustbe raised accordingly. Now as the flow of current increases to supply the demand on the working circuit the current through the auxiliary winding 5 increases proportionally, and consequently reduces'the magnetic effect of the main winding 4, and as the result the core of magnet AG drops proportionately, thus varying the position at which the contacts 0 and c operate, thereby permitting the regulator One winding, 5, of 'the magnet AG is in circuit with the secondto operate at a higher generator voltage and to maintain this higher voltage at the generat or, and consequently maintaining a constant voltage at the distautplace of use.

To give one set of proportions which will be a guide in reproducing the apparatus, it maybe stated that in practice I have used eight convolutions in the primary 32 of the transformer U, one hundred and sixty convolutions in the secondary'34 of said transformer, eleven hundred ampere-turns in the main winding 4-, and one hundred and ten ampere turns in the auxiliary winding 5. These details will, however, vary in accordance with conditions in each particular case, as will he'understood by skilled electricians. The transformer U may be omitted and all or a portion of the total current may pass directly through the auxiliary winding 5, which in such case would have very few turns.

The diagram Fig. 2 shows a complete sysof which is a portion of the main A.

thiscircuit.- Theprimary'ofsaid transformer, is in a shunt A A of the alternator-mains A A The auxiliary winding 5 of the mag net AC is in'the circuit A. A of the second- A switch L 'en'ables the main current to fiow across the transformer U, thus enabling the current tobe maintained in case of damage to the transformer or in case it is desired'to render that part of the regulator inoperative. The direct controlling-magnet DC is in the shunt-circuitE E from the exciter-mains E" E the incandescent lamps F FF being in'this shunt-circuit. In this diagram the relay D is not operated by an independent generator, but is in a shunt D D from the excitermainsEE Thecircuit-wiresDD leadtothe reversing-switch H, the cutoff-switch N being employed in this circuit and the lamps GGG being therein, all as in said application Serial No. 12,721. Conductor D leads-from the reversing-switch to post 1', where it branches, branch D, leading to the lever (11, and hence then passing to post 25 and by conductor D to the return-wire, Dflso that cu rreutconstantly flows through'the windipg R, thus normally attracting the armature 30 against th'e'ten-- sion of retracting spring Q, and hence ciosing the relay-contacts d d. When, however, the controlling-contacts c c are closed, the current flows from conductor I) through lever al, cont-acts c c, lever (11, and conductor 1) to post 5, and thence around the other winding, S, of the relay through conductor D to post t, and thence by conductor D to the return-wire D thus sending current around the relayin the opposite direction to that flowing through winding R,thus neutralizing thesame,demagnetizing the relay, and permitting spring Q to withdraw the armature 30, and hence to separate the relay-contacts d 01, thereby producing the same effects as previously described herein in relation to the diagram Fig. 1. The contactsdd control the regulating resistance B in the same way as in said application, Serial No. 12,721. The shunt-wires B B bridge across the resistance B. These wires lead to the reversing-switch I, which is connected by wires 13 -13 to the contacts (1 and (1, respectively, and a bridge B 'and 8 across said wires contains a condenser V- to'lessen sparking at said contacts,- all as in said application. These circuit connections diiferfrom those of said application owing to the presence of the controlling-switch J and the starting-switch K.

3, 12, and 13t It is a two-pole switch coniprising two mechanically-connected conductary of the-series transformer U, the primary to main contact 0, and the branch D leading to the winding R ofthe relay, the current The controlliug-switcli J is shown in Figs.

ing-bars43 43, insulated from each other, each being pivotally connected to a metal conducting base-plate 44in justthe same way as are cation, Serial No. 12,721.

Bgjle'ad .to these plates 44 44, respectively. Thcsepivoted conducting-bars 4-3 43 swing simultaneously into and out of contact with spring-clip contacts 45 45, carried, respectively, near the upper-ends of posts 46 46, which latter are connected by appropriate wires with the proper terminals ofthe reversing-switch I. Fig. 12 shows the bars 43 in such position that relay-contacts d d are not in circuit. By swinging said bars toward the contacts 45 electrical connection is made at two places simultaneously, thus bringing said relay-contacts d d into operative relation to the exciter. By manipulating this switch J it will be noted that the entire regulating effect of the'regulator can be controlled. VVh'eu this switch is open, the regulator is inoperative, and the entire field-current of the exciter must pass, all of the time through the resistance B.

The starting-switch K is for the purpose of enabling the fieldof the exciter to build up quickly on starting the generator. -As shown in Figs. 3 and 12, this switch K is-pivoted loosely to one of the plates 44, and it normally hangs by gravity in theposition shown in Fig. 12, where itisinoperative. By swinging-it up to the position shown in Fig. 3 it connects the two plates 44, 44' electrically, thus bridging across the resistance'B temporarily, thus cutting oif all extraneous-re; sistance in the field-shunt of --the .ex citer' E, :and hence enabling it to build up'rapidly. In the meantime the switch J is closed, and then when the generator is in proper operation the switch K is let go. It resumes its inoperative position by gravity, and the'reguiator and resistance B are left in full opera tion.

To avoid dangerous rise of potential in case of accident to the circuit ofeither of the con trolling-magnets AC or DC, protecting means are employed similar to those -employed in said application Serial No. 12,721. Stop g for lever dl is connected by wire G2 with conductor D and the stop g-for lever al is connected by wire G with conductor D Consequently if the conductor supplying current to either magnet AC or DC fails-the correspondtectin'g-stop, the circuit from D to D will be permanently closed, the winding S'of relay D will be permanently in circuit, the relay-conwisiajthe regulating resistance B will be permanentlyjn circuit, hence preventing dangerous rise in potential and having the same efiect as if the regulator was not in use.

been described the regulatiu magnets AC' and DC are so arranged that their contacts ing lever will be pulled back against its protacts d df'will bepermanently open, and like In the arrangements which have 'thus far the pivoted metal bars of the reversiugswitches H and I, as described in said appli-- The conductors B 0'. come together as the potential rises and separate as itfalls. I prefer, however, to arrange the apparatus so thatjust the opposite effect shall take place, thesame ultimate end to 25, inclusive, which figures areas follows:

'As shown in Fig. 19, the alternator-magnet lever al is below the direct-magnet lever dl, thus bringing contact .0 below contact 0 instead of above it, asbet'ore. The levers are pivot-ed atp and the same retracting-springs are employed. The spring e is shown, but not the spring e, which, however, may be employed, and, if so, is connected to asleeve on the arbor 14 just as before. The contact a is formed bya screw adjustable vertically in block 46, Fig. 21, and held by set-screw 47, said block being soldered or otherwise connected to the outer end of spring-arm 1, which is adjnstableby post 2 and slot 3, as before. The other contact cis carried near the end of a spring-arm 48, which is connected to but insulated from the lever al. The tension of this spring-arm is regulated by adjusting screw 49, tapping through the lever, insulation being secured in any suitable manner, as by making said screw of hard rubber. Springarm 4Sshonld be adjusted so as to be stiffer than spring-arm 1. The lever al has a lateral oifset50, which carries the arm 51, having the adjusting-weight 28, as shown in Fig. 20, so that there will be no interference with the lever (ll. is secured one end of a spring-arm 52, in electrical connection with the lever (11, and hence with the conductor D, said arm having a contact 53, which registers normally with an auxiliary contact 54 on the spring arm 48 near the contact 0. Figs. 19 and 21 show these "contacts 53 and 54 separated to facilitate understanding their relation; but normally they are'in contact, so that normally the contact 0 is in electrical connection with the conductor D Thepurpose ofthese auxiliary contacts 53 54 is for the purpose of.

protection incase of accident, as will hereinafter he explained. The relay-contacts d d are arranged just opposite to those of the re-' lay shown in Figs. 2, 3, 7,'and 8. In this case the armature 30 is beneath the post 31, which carries the spring-contact d, thus bringing armature-contactd beneath the contact tlinstead of above it, as before. The spring-contact d is carried by a plate 55, which is adjustable on the post 31 by screws 50 and slot 5'7. The spring Q for elevating the armature 30 is shown in Fig. 24:. The movement of armature 30 toward the magnet D is limited by fixed stop 58. This timproved and preferred arrangement of relay and controlling levers is shown in the diagram Fig. 25, which is simplified as much as tage to rise.

To this offset 50 (see Fig. 21)

possible. It will be understood, however, that it-is preferred to employ with this arrangement the various transformers, noninductive resistances, reversing-switches, condensers, and other adjuncts shown in Fig. 2, but which are omitted from Fig. 25 to facilitate understanding thereof. when there is no voltage the contacts 0 c are pulled toward each other, and as the result the-auxiliary contacts 53 and 54 are forced apart',"thns breaking the circuit through the conductors D and D and consequently no current flows through the winding S of the relay. If at the same time there be no current in the relay-winding R, as will be the case if it obtains its current from the same system as the magnet D-C,-as shown in Fig. 25, the spring Q acts and keeps the contacts In this case t d d closed, and this may ordinarily be re garded as the condition of affairs with no vol tage. In this condition, with the relay-contacts closed, the regulating resistance is out out, and consequently the cxciter is in condition to build up rapidly when the generator is started, thus doing away with a special starting-switch and starting-rod. \Vhen the system begins to operate the contacts 0 o are closed, both differential relay-circuits R S are closed, thus demagnetizing relay-cores, and allowing armature 30 to follow the pull of its spring Q, and its contact at is in contact with upper or stationar y contact d This cuts out the regulating resistanceB, allowing vol- As soon as voltage rises both controlling magnets AC and DC begin to strengthen and open the main lever-contacts c c,when the normal voltage is reached. This in turn opens the differential relay-circuit S, and therelay-core,becoming magnetized,overcomes the tension-spring Q and draws armature 30, with itscontact d,down against-stop 58, thereby opening relay-contacts and'throwing in the regulating resistance B. This action continues to and fro as long as the regulatoris in operation. The advantages of this preferred type of regulator are as follows: The exciter voltage in sudden and extreme changes in the alternating load cannot go low enough with this new type of regulator to throw it out of operation, as the relayacontacts its even with no voltage in relay-cores would be closed and would tend to build the voltage up to normal before opening again. It avoids the yawning effect sometimes caused in the first-described regulator in main lever-contacts c c by sudden changes in load orspeed, as said contacts now tend to lie together. As the preferred regulator will start itself, the use of any starting-switch, such as the switch K, and the raisihgup of the corev 6 by hand through rod 24 are avoided, and these'deviccs are omitted. All the circuits remain the same as in the first-described regulator, with the exception that main contacts and relay-contacts Work inexact opposition, and the pr0- tecting-wires G G are omitted. The protecting-wires G G are not necessary, because in case either magnet AC or DC gives out the ci rcuit through relay-windings is broken, and consequentli the current flowing through winding Rkeeps the armature held down, thus keeping contacts (1 d separatedpand hence leaving the regulating resistance B in full permanent operation, thus preventing dangerous rise of potential in the alternatormains. Y

The present improvements although espe cially applicable to the regulation of alterhating generators are also admirably adapted llD -lYlFU n6lS em lo ed with a separatel -exs e P 5 v merits.

cited direct-murrent generator Y, with a relay D, energized by a shunt from the generator-mains. ,It will be readily understood without specific illustrations that various of.

the auxiliary features previouslydescribed are applicable to. either of these arrange- The present improved regulator can also be employed i'or thesimultaneous' regulation of a plurality of generators, either alternat ing or direct, will be readily understood by the skilled electrician. Among the arrangementsiwhich will readily suggest-themselves may he mentioned the following: First, a plurality of alternating generators feeding the'same mains can be arranged each with its own exciter and regulator, and this I prefer; second, a plurality of .generatorsfieeding 'the same mains, with their several eXciters in parallel, can be used with a single regu- .lator controlling all of their rheostats simul-- t'aneonsly, equalizing resistances being employed if necessary; third, a'plurality of gem eratcrs canibe used to feed the same mains with independent exciters, any one of which .exciters may be used for all of the generators,

with a single regulator adapted to he brought into connection with the particular exciter in a plurality'of' generators can feed the same mains, and a-single exciter'can be used there;

for with a single regulator. The last of these suggested arrangements is shown'in Fig. 28, in which A and AA are two altern'ators and E is the common exciter therefor. The various connections for the .instrumentsof the I use hymeansof appropriateswitehes; fourth,

departing from the spirit of theinvention.

For a further example itmay befstated that if the compound winding of the alternator controlling-magnet is employed the series transformer U may be omitted and one or two turns of one of the main feed-conductors can pass directly aronnd said magnet.

What I claim as new, and desire to secure by Letters Patent 6f the United States, is- 1. The method of regulating the voltage of a dynamo-electric machine, which consists in exciting the field of the machine, controlling said excitation" in response to the voltage at the regulated p0int,,and causing the excitation voltane to react upon the control independently of its action through the fields o the machine and of the exciter. 1

2. Jlhe methodof regulating an alternatingcurrent generator, the field of which is ener gized by an exciter, which consists in regulating the field resistance of the exciter in response both to the exciter voltage and the Voltage of the generator.

electric machine, which consists in exciting the fi eld of said machine from an independent source of current of variable voltage, and regulating said source of current in response bothfto its own voltage and to the voltage of said dynamo-electric -machine.

In witness whereof I have hereunto set my hand-this 24th day of September, 1902.

ALLEN A. TIRRILL.

Witn esses:

or HELEN ORFORD,

G. C. HOLLISTER.

3. The method of regulating a dyname 

